Leaf spring assemblies are conventionally used for suspending one component relative to another. Vehicle suspension is one example of an application using such assemblies. However a leaf spring assembly can be used in many different situations and the present invention is applicable to any of these and is not intended to be limited to vehicle suspensions.
A four spring suspension system used extensively in the highway transportation trailer industry features four leaf spring assemblies. Each of these leaf spring assemblies includes a plurality of individual leaf springs of varying lengths stacked one atop the other and connected together at approximately a center point along their length. The longest leaf spring has its ends shaped to be supported on spring hangers attached to the frame of the vehicle. An axle seat is attached to the center of the leaf spring between the two ends for attachment to an axle of the vehicle. In this particular suspension system, leaf spring assemblies on separate axles are connected at a common hanger to an equalizer which distributes the vehicle weight between the two axles.
Typically, these leaf spring systems do not incorporate deflection limitation devices to protect the leaf springs from potential failure precipitated by overloading. Instead, this type of suspension relies on significant safety factors within the design to protect against overload. If overload does occur the leaf spring may fracture and there is no method of containing the fractured pieces within the vehicle. Subsequently, if a spring fails, the broken pieces generally dislodge from the vehicle and represent a danger to the public. As a result, there is a demand for a device that protects the public by assuring that in the event of a leaf spring fracture within the leaf spring assembly, the components remain attached and continue to travel with the vehicle.